(a) Field of the Invention
The present invention relates to a door gripper used during manufacturing of a vehicle. More particularly, the present invention relates to a door gripper for a vehicle which is configured to correspond to an angle difference of restricted cross sections and height and width differences of restricted cross sections of a door of a vehicle to be applied to a various types of doors. The present invention also relates to methods of manufacturing a vehicle using a door gripper.
(b) Description of the Related Art
Grippers are typically mounted at the end of an arm 3 of a robot 1 used in the manufacturing process, such as for example the gripper 5 shown in FIG. 1. Such a gripper is used to carry vehicle body parts from one manufacturing process to the next manufacturing process of the vehicle assembly line or to fix the vehicle body parts for welding by a welder in the vehicle body assembly line. Such a gripper also is typically called a robot gripper.
In FIG. 1, reference numeral “7” indicates a welder and reference numeral “9” indicates a door, which is a part of a vehicle body.
There is shown in FIG. 2 a conventional door gripper 5. Such a door gripper 5 includes four exclusive clamping units 13 and a variable clamping unit 17 provided with two sliding cylinders 15 on a frame mounted at the end of the arm 3 of the robot 1.
When using such a conventional door gripper 5, when (a) the angle or height of restricted cross sections of vehicle parts is different, or (b) the shape of the restricted cross section is complicated for each vehicle, or (c) to prevent interference with the existing equipment, one uses the sliding cylinder 15 with the variable clamping unit 17 to handle one or more of these concerns. However, when these concerns cannot be addressed for new types of vehicles, even by using the variable clamping unit 17 and the sliding cylinder 15, an entire new gripper is manufactured for the new types of vehicles.
Consequently, when an exclusive gripper is provided for new types of vehicles, the investment cost is increased because of the additional cost for either modifying an existing gripper or manufacturing a new gripper. In addition to the added cost, the structure of the gripper becomes gradually more complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.